Apparatus for casting under pressure



Sept. 18, 1928.

E. JORGEN-JENSEN APPARATUS FOR CASTING UNDER PRESSURE Filed Nov. 21,1927 Patented "Se t. 1a, 1928.

, UNITED sures am Joanna-muslin, or :anenasrou, nmnrmenm, nnenmn.

arranarus iron cas'rme unnnia rnnssuan. 1

Application fled November 31, 192?, Serial No. 884,772, and in DenmarkMarch 22, 1827.

My invention relates to the production of castings under pressure.

Within recent years the use of air pressure in foundry pract1ce hasfound favour for the reason that good filling of the moulds and greaterdensity of metal can thereby be secured. The apparatus employed forpressure casing however, frequently sufiersfirom the drawback that thecrucible contalnmg the m molten metal, after a period of use, becomescracked or ruptured for the reason that it 1s unable to withstand thedifierential pressure to which it is subjected.

To avoid this drawback it has been ro- 1 posed to enclose the crucibleina cover or ll to which the'air pressure is sup lied so that thecrucible, both externally an internally, is subjected to uniformpressure conditions. With such an arrangement there still exists thedrawback that it is not readily possible to evacuate the crucible of allmolten metal in the casting-operation and consequently the outlettherefrom and the inlet to the mould are likely to become choked withchilled metal. I

The apparatus according to the present invention is characterized by thefact that the molten metal, by combined air pressure and syphonicaction, is caused to run through a w tube in the bottom of the crucible,while the saidcrucible is surrounded by a compressed air bell in such amanner that the walls of the crucible are not exposed to anydifferential pressure.

- One construction of the improved a paratus is illustrated in verticallongitu inal section in the accom anying drawing.

Referring to the atter, 1 is a plate below which the mould 2 isdisposed, in such a manner that the gate 3 of the same is situateddirectly below the corresponding opening 4 in the plate 1. Above thisopening there is placed on the plate a crucible 5 at the centre of whichthere is provided a tube ,6 the mouth of which, as shown, is situatedabove the normal level of molten metal in the crucible, and which isadapted, when the crucible is placed in position, to communicate withthe opening 4 of the plate 1 and the gate 30f the mould 2.

, Over the crucible and on the plate there is placed a bell 7 from whicha smaller bell 8 is suspended, which latter, when the hell 7 is inposition, projects down to the bottom of the crucible and encircles thetube 6, holes being provided, however, at the bottom edge of the 7 bell8, in such a manner that the masses of molten metal inside and outsideof the bell 8 will be in communication with one another. By way of apipe 9 compressed air maybe directed into the hell 7, in such a mannerthat the molten metal contained in the'crucible 5 outside the bell 8,owing to the air pressure, will be pressed through the holes at thelower edge of the hell 8 up the interior of the latter and down the tube6 into the mould 2. As the quantity of molten metal in the crucible 5may be adjusted to correspond to the volume of the mould, the airpressure, after the mould has been filled,will act directly on the metalcontained in the mould. Furthermore, owing .to the provision of the hell8 and the particular arrangement of the latter with respect to the tube6, It will be observed that when the molten metal flows into the tubedue to the pressure applied to it a syphonic action will be set up. Thisaction will not only assist in the evacuation of the crucible but willaug- .ment the air pressure acting directly on the metal in the mould.

In the herein described embodiment the constructional details have beenomitted for the'sake of simplicity, but obviously means must be rovidedfor securing a connection between t e mould 2 and the plate 1 andbetween the latter and the bell 7 as well as for suspending, in suitablemanner, the interior boil 8 from the outer bell 7. In the latter respectthe means may comprise a spring 10 as shown. Y a

What I claim and desire to secure by Letters Patent of the'United Statesis':-

1. Apparatus for casting under pressure, comprising a crucible adaptedto contain molten metal, an outlet from said crucible, means for causingthe molten metal to flow through said outlet by combined air pressureand syphonic action, and a compressed air bell surrounding said cruciblesuchwise that the walls of the crucible are not exposed to mdifierential pressure.

2. Apparatus for casting under pressure, comprising a crucible adaptedto contain molten metal, an outlet from said crucible, a a mould, meansfor causing the molten metal 105 to flow through said outlet into saidmould by combined air pressure and syphonic action, and'a compressed airbell arranged suchwise that the walls of the crucible are free fromexposure to difierential pressure, said air no tom of said crucible andhaving an outlet adapted, when the crucible is laced in position tocommunicate with an i et to a mould, a bell coverin said crucible, meansfor supplying air un er pressure to the interior of the said bell, andanother bell arranged within said first mentioned bell and covering saidtube, for the pur ose set forth.

4. Apparatus or casting under pressure, comprismg a crucible adapted tocontain molten metal, a tube extending upwardly from the bottom of saidcrucible, an outlet to said tube adapted to communicate with an 1 inletto a mould, abell adapted to cover said crucible, means for supplyingair under pressure to the interior of said bell, another bell arrangedwithin said first mentioned bell and covering said tube and means forsuspending said second mentloned bell from said first mentioned bell,for the purpose set forth.

5. Apparatus for casting under pressure, comprising a mould, a crucibleadapted to contain molten metal a tube extending from the bottom of saidcrucible and having an outlet adapted to communicate with an inlet tosaid mould, a bell covering said crucible, means for sup lying air underpressure to the interior 0? said bell, and another bell situated withinsaid first mentioned bell and around said tube the arrangement beingsuch that the crucible is evacuated of molten metal by combined airpressure and syphonic action and such that said air pressure actsdirectly on the metal in the mould and'is augmented by said syphonicaction.

ERIK J ORGENJENSEN.

